Known V-type, two-cylinder, four-stroke cycle internal combustion engines such as those utilized in numerous motorcycle vehicle applications function satisfactorily during normal highway usage but have a pronounced tendency to fail following extended operation at high output power levels. The modes of failure often are attributed to phenomena such as connecting rod distortion, crankshaft assembly flexing, and insufficient lubricant flow to bearings. In some cases the failure can be further attributed to the use of co-planar connecting rod elements that are conventionally joined to the engine crankshaft assembly crank pin element by means of a combination of straight and forked (clevis-type) connecting rod ends and their attendant connecting rod bearings. This construction may be seen in engines having a pair of opposed pistons the axes of which lie in a common plane perpendicular to the axis of the crankshaft.
I have discovered that the failure frequency of such engines under conditions of high power output may be significantly reduced by incorporating an improved connecting rod end and connecting rod bearing arrangement in such engines. Also, improvements to lubricant flow and lubricant distribution to the connecting rod bearings are achieved in the invention as well as reduced flexing of the engine crankshaft assembly during encountered high speed operation.
Other objects and advantages of the present invention will become apparent during a consideration of the descriptions, drawings, and claims which follow.